1. Field of the Invention
The present invention relates to floating electrical connectors.
2. Description of the Related Art
Floating electrical connectors include a fixed housing, a floating housing, and contact elements provided in the housings. The contact elements have an intermediate sections between a connection section on the side of the fixed housing and a contact section on the side of the floating housing to make the floating housing movable.
A plurality of such connectors are mounted on a circuit board and plugged into a plurality of mating connectors on another circuit board while the floating housings absorb errors in the mounting positions of these connectors.
Japanese patent application Kokai No. 310197/94 discloses a connector of this type. As FIG. 6 shows, the connector includes a fixed housing 51, a floating housing 52 provided above the fixed housing 51, and contact elements 53 mounted on both the housings 51 and 52. The contact elements 53 are arranged with a predetermined pitch in a first direction perpendicular to the sheet.
The inside portions 53A of the contact elements 53 are attached to the floating housing 52 while the outside portions 53B are attached to the fixed housing 51 which is fixed on the a circuit board S by soldering or the like. The contact elements 53 have U-shaped portions for attachment to the fixed and floating housing 51 and 53. The inside and outside U-shaped portions are united by an intermediate arm 53C. The intermediate arms 53C are flexible in a second direction parallel to the sheet to make the floating housing movable.
A mating connector (not shown) is plugged into the connector such that the contact portions of the mating connector are brought into contact with the contact portions 54D of the inside portions 53A. If there is an error in the mounting position between the connectors, the intermediate arms 53C are flexed so that the floating housing 52 is moved in the second direction to the correct plugging position.
Japanese patent application Kokai No. 325825/94 discloses another connector such as shown in FIG. 7. The connector includes a fixed housing 61 and a floating housing 62 provided on the shoulder portions of the fixed housing 61 so as to be movable in the second direction. The inside bottom 62A of the floating housing 62 is close to the circuit board S. A plurality of contact elements 63 are arranged in a zigzag fashion with a half pitch offset from each other in the first direction. The contact elements 63 have an outer section 63A, which has a connection portion connected to the circuit board S, attached to an attaching groove of the fixed housing 61 and an intermediate section 63B (and a projection thereon) attached to the floating housing 62. The inside sections of the contact elements are bent in a U-shaped form to provide contact portions 63C.
A mating connector (not shown) is plugging in the cavity of the connector. A positional error is absorbed by a flexible portion between the outside portion 63A and the intermediate portion 63 of the contact element 63.
There is a demand for a low profile connector able to absorb a mounting error. In the connector of FIG. 6, however, the floating housing 52 is provided above the fixed housing 51 so that the distance between the two circuit boards is large. The mobility of the floating housing 52 depends on the flexibility of the intermediate arms 53C which only extend downward from the top of the contact elements 53 so that the amount of flexure in the second direction is small, and little twist is permitted. Consequently, the mobility of the floating housing 52 is small.
In the connector of FIG. 7, the bottom of the floating housing 62 is close to the circuit board P, but the periphery is mounted on the fixed housing 61 so that it is difficult to reduce the height as in the connector of FIG. 6. The mobility of the floating housing 62 depends on the flexibility of a portion between the intermediate portion 63B and the outside portion 62A of the contact elements 63, but the distance between the two portions 63B and 63A is so small that the amount of flexure is small. In addition, the contact elements 63 are so thick in the first direction that little twist is permitted.
Thus, it is difficult to reduce the height of the above two connectors, and the mobility of the floating housing is small. In addition, the floating housing is movable in only the second direction.